Circuit-breaker.



P. H. THOMAS.

CIRCUIT BREAKER. APPLICATION FILED JAN. 6, 1905. RENEWED FEB. 19, 1907.

PATENTED JAN. 14, 1908.

UNITED STATES" "PATENT OFFICE.

PERCY H. THOMAS. O l )IOXTCLAIR, NEYYJERSEY, ASSIGXOR 'lO COOPER HEWITT ELECTRIC 'CO.\'lP lXY,.OF NEW YORK, N. Y., A CORPORATIOX 01' NE: YORK.

' CIRCUIT-BREAKER.

No. 876,918. Specification of Letters Patent. Patented Jan. 14, 1908.

Original application filed December 10. 1903, Serial No. 184.540. Divided and this application filed Jannaryiti. 1905. Serial No. 239-839- Renewed February 19- 190'7. Serial No. 358.218.

To a-ll'u'lzom it may concern: vaporizable material within the chamber 55 Be it known that I, PERCY H. THOMAS, a usually mercury-which is heated bv the citizen of the United States, and resident of passage of current. It becomes, then, a

Montclair, county of Essex, State of New question of properly proportioning the di- Jersey, have invented certain new and useful mensions of the chamber so as to give it a- Improvements in Circuit-Breakers, of which definite heat radiating and heat absorbing co the following is a specification. capacity. This done, a vapor circuit-breaher In an application for Letters Patent of the may be made to operate with certaint with- United States filed by me on the 27th day of in such limits as may be prcdetermiucd.

June, 1903,.Serial Number 163,307, I have The accompanying drawing illustrates av shown and described a form of'circuit-breaker circuit-breaker embodying my invention. especially adapted for use in connection with Referring to the drawing 1 is a container of alternating current circuits, the significant insulating material having lead-wires 2 and 3 feature being that the circuit 'is broken sealed into its ends, the said lead-w i1cs,l)cing 15 between surfaces inclosed in an exhausted connected inside the container by a mass of chamber. When such a circuit-breaker is mercury, 4. The (llCLll'C-lJlOzlliGI is located included in an alternating current circuit, inahorizontal position and in this particular the rupture of the arc takes place when the form may be arranged in a shunt to a. switch current momentarilyceases at the zero point of comparatively low resistance which carof the wave, andcannot start again, this be-- ries the normal current of the circuit. The ing accomplished without any injurious rise container 1 is made of small cross-section and 0f potentialin the external circuit. The decontains in the major portion of its length a scribed circuit-breaker may also be applied small amount of mercury bridging the electo circuits conveying currents naturallyvary trodes, into which the lead-wires 2 and 3 ex- 25 ing, provided the lower limit of variation is tend at opposite ends of the circuit-breaker.

below the carrying limit of the circuit- I may provide small condensing chambers, 6 so breaker. and 5, above the resiective electrodes.

In this application I disclose a circuit- The switch whichcarries the normal curbreaker which may also be utilized in conrent is shown at 6, and when thisswitch is 30 neotion with alternating current circuit, but opened, the ntire normal current is diverted which is more part-irula-rly adapted to be through the circuit-breaker, whereupon, used in connection with direct current cirowing to the thinness of the layer of mercury Quits, extending through the major portion of the In the present instance, the interruption tube, a portion of the mercury or other con- 35 of the circuit is accomplished by the gradual ducting liquid is vaporized, creating a high introduction of a resistance to the flow of vapor pressure for the purpose already set current through increasing the pressure withforth. It will be seen that. the development in the exhausted chamber. In gas or vapor of high vapor pressure in the circuit-breaker apparatus of this character, the resistance to under these conditions is gradual; that is 40 the flow of current, or, in other words, the to say, the point of actual rupture of the cirvoltage necessary to pass current, is greatly cuit is reached through comparatively small increased as the pressure of the vapor within gradations. Accordingly, all tendency to the exhausted chamber rises. Ap aratus of create an injurious rise of potential in the exthis class will not pass current belbw a cer ternal circuit is avoided. v 45 tain definite limit of electro-motive-force, The present application is a division of my and when the chamber is made of a proper application Serial Number 184,540, filed Deheat radiating and heatabsorbing capacity, cember 10, 1903. this limit may be so fixed that while a nor- In a companion application, Serial Nummal current will flow through the apparatus ber 163,307, filed June 2-7, 1903, claims are 50 an abnormal current will be prohibited from made upon some of the broader features of assing through and the current will cease. the invention disclosedherein. n this connection it is to be remembered I claim as my invent1on:- that the pressure in the exhausted chamber 1. The combination with an electric onis determined by the temperature of the cuit and a main switch included therein. of a the passaie of current upon the opening of said switc .2; The combination with an electric circuit and a-main switch included therein, of a gas or vapor electric circuit breaker in shunt to said switch, the said circuit breaker including a suitable hermetically sealed and completely exhausted container having mercury electrodes therein initially connected by a thin body of mercury of such dimen sions as to be vaporized by the passage of current therethrough'on the opening of the 7 switch.

3. The combination with an? electric cir- 'cuit, and a main switch included therein, of a circuit-breaker in shunt to the switch, the

said circuit-breaker being composed ofa suitable contalner having mercury electrodes connected by a thin body of mercury. Signed at New York, in the county of New York, and State of New York, this Sth'day" of January, A. Dr

1905'. PERCY H. THOMAS.

Witnesses:

.WM H. CAPEL, v "GEORGE H. STOCKBRIDGE. 

